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1

Digitale Medien

Correspondence of phase separation in several charged particle systems (1992)

McGahay, Vincent ; Tomozawa, Minoru

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 97 (1992), S. 2609-2617

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ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: This paper demonstrates the close correspondence in phase-separation behavior of a variety of systems which contain charged particles. These include electron-hole fluids in semiconductors, oxide melts and glasses, and molten salts. Reduced critical parameters for the fifteen systems considered are calculated using the theory of corresponding states for ionic fluids. The reduced critical parameters are found to be in close agreement, indicating that the different systems exist in corresponding states at their critical points to a good approximation. A model of phase separation based on Debye–Hückel theory is presented. The usual limitations of the theory due to the linearization of the Poisson–Boltzmann equation as well as neglect of excluded volume effects due to hard core interactions are avoided by employing the dissociation/association equilibrium of Fuoss. The theoretical critical parameters which are derived are in excellent agreement with experimental data. The degree of dissociation is calculated to be about 3% at the critical point, which is in the expected range of a few percent.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.463049

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2

Digitale Medien

Detection of Phase Separation by FTIR in a Liquid-Crystal-Display Substrate Aluminoborosilicate Glass (2001)

Kato, Yoshinari ; Yamazaki, Hiroki ; Tomozawa, Minoru

Westerville, Ohio : American Ceramics Society

Journal of the American Ceramic Society 84 (2001), S. 0

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ISSN: 1551-2916

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Maschinenbau , Physik

Notizen: The effect of heat treatment on the Fourier transform infrared spectrometry (FTIR) reflection peak position of the Si–O structural band near 1087 cm−1 of a liquid-crystal-display substrate glass was investigated. The FTIR peak position shifted more slowly with heat-treatment time, and to a greater extent than expected, for the fictive temperature change. The isochronal shift of the FTIR peak as a function of the heat-treatment temperature exhibited a good correlation with the change of chemical durability in an HCl solution, suggesting that the infrared peak shift was the result of the phase separation induced by the heat treatment. The separated phase, with spherical particles ∼50 nm in diameter, was observed by scanning electron microscopy in a glass sample heat-treated at 750°C for 2500 h. The FTIR peak shift measurement appears to be a sensitive method for detecting the early stage of the glass-in-glass phase separation for borosilicate glasses.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb00967.x

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3

Digitale Medien

Subcritical Crack Growth in a Phosphate Laser Glass (1999)

Crichton, Stephen N. ; Tomozawa, Minoru ; Hayden, Joseph S. ; [weitere]

Westerville, Ohio : American Ceramics Society

Journal of the American Ceramic Society 82 (1999), S. 0

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ISSN: 1551-2916

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Maschinenbau , Physik

Notizen: The rate of subcritical crack growth in a metaphosphate Nd-doped laser glass was measured using the double-cleavage-drilled compression (DCDC) method. The crack velocity is reported as a function of stress intensity at temperatures ranging from 296 to 573 K and in nitrogen with water vapor pressures ranging from 40 Pa (0.3 mmHg) to 4.7 × 104 Pa (355 mmHg). The measured crack velocities follow region I, II, and III behavior similar to that reported for silicate glasses. A chemical and mass-transport-limited reaction rate model explains the behavior of the data except at high temperatures and high water vapor pressures where crack tip blunting is observed. Blunting is characterized by an arrest in the crack growth followed by the inability to reinitiate slow crack growth at higher stresses. A dynamic crack tip blunting mechanism is proposed to explain the deviation from the reaction rate model.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1151-2916.1999.tb02208.x

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4

Digitale Medien

A Source of the Immiscibility Controversy of Borate and Borosilicate Glass Systems (1999)

Tomozawa, Minoru

Westerville, Ohio : American Ceramics Society

Journal of the American Ceramic Society 82 (1999), S. 0

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ISSN: 1551-2916

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Maschinenbau , Physik

Notizen: Because phase separation affects glass properties such as chemical durability, it is important to clarify this phenomenon, especially the immiscibility boundaries. Despite extensive investigation, controversy persists in regard to the immiscibility boundary of borate and borosilicate systems. The controversy has been suggested to originate from a change in glass structure with heat-treatment temperature or fictive temperature, which, in turn, causes a change in the immiscibility tendency.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1151-2916.1999.tb01743.x

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5

Digitale Medien

Properties of Na2O·3SiO2 glasses impregnated with ethyl alcohol (1983)

Nogami, Masayuki ; Tomozawa, Minoru

Springer

Journal of materials science 18 (1983), S. 2453-2458

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ISSN: 1573-4803

Quelle: Springer Online Journal Archives 1860-2000

Thema: Maschinenbau

Notizen: Abstract Na2O·3SiO2 glasses impregnated with up to 8.5 wt% ethanol were prepared under high pressure and hydrothermal conditions and their properties such as hardness, fracture toughness and density were measured. Both hardness and density increased initially with increasing ethanol content up to 1∼2 wt% ethanol and then decreased with further increase in ethanol content, while fracture toughness decreased monotonically. This initial increase of hardness and density of ethanol-impregnated glasses is in contrast to the behaviour of glasses with high water content, which showed a steadily decreasing hardness and density with increasing water content. A structural study using IR and X-ray diffraction analyses was also made and changes in properties of glasses with increasing ethanol was related to the formation of Si-O-C bonds and the precipitation of sodium carbonate crystal.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00541851

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